Team spokesman Kevin Best announced the suspension Friday.
Chapel Hill police records indicate Simmons was arrested early Wednesday morning on Franklin Street and charged with resisting arrest.
He also faces an Aug. 3 court date after he was arrested May 16 on a misdemeanor charge of marijuana possession.
The 21-year-old Simmons, from Lehigh Acres, Florida, started five of 12 games last season for the Tar Heels. He had 34 tackles, three passes broken up and a forced fumble.